Packet-based digital display interface signal mapping to micro serial interface

ABSTRACT

A passive cable adaptor for connecting a data source device with a display device is described. The adaptor has a packet-based interface connector at one end, the connector having a positive main link pin, a negative main link pin, a positive auxiliary channel pin, and a negative auxiliary channel pin. At the other end is a micro serial interface connector, wherein multimedia content is transmitted over the cable adaptor and electrical power is supplied over the cable adaptor simultaneously. The cable adaptor has an auxiliary and hot plug detect (HPD) controller utilized to map the auxiliary channel and HPD signals of the packet-based digital display to the micro serial interface ID signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 14/045,070, entitled “PACKET-BASED DIGITAL DISPLAY INTERFACE SIGNALMAPPING TO MICRO SERIAL INTERFACE,” filed on Oct. 3, 2013, which is adivisional of U.S. patent application Ser. No. 12/862,087, entitled“PACKET-BASED DIGITAL DISPLAY INTERFACE SIGNAL MAPPING TO MICRO SERIALINTERFACE,” filed on Aug. 24, 2010, which claims priority under 35U.S.C. § 119(e) to Provisional Patent Application No. 61/300,929, filedFeb. 3, 2010, titled “SIGNAL MAPPING BETWEEN DISPLAY PORT AND USB3.0COMPLIANT DEVICES”, Provisional Patent Application No. 61/318,727, filedMar. 29, 2010, titled “DP SIGNAL MAPPING ONTO A USB CONNECTOR”, toProvisional Patent Application No. 61/325,734, filed Apr. 19, 2010,titled “DP SIGNAL MAPPING ONTO MICROUSB2.0 CONNECTOR”, and toProvisional Patent Application No. 61/365,195, filed Jul. 16, 2010,titled “DISPLAY PORT AUX CH HANDSHAKE FOR NEGOTIATING A HIGHER POWERSUPPLY VOLTAGE”, all of which are incorporated herein by reference intheir entireties. Application Serial No. 12/862,087 is assigned to theassignee of the present application and is hereby incorporated byreference into the present application as if fully set forth herein. Thepresent application hereby claims priority under 35 U.S.C. § 120 fromU.S. patent application Ser. No. 12/862,087 to the maximum extentallowable by law.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to communication of varioustypes of data in a multimedia network. More specifically, it relates tocommunicating data directly between a multimedia device and an externaldisplay device.

BACKGROUND OF THE INVENTION

Many multimedia devices are becoming increasing popular. Such devicesare being used more frequently as devices for taking and storing videos,picture, music files and software applications (“apps”) and the like,for a wide variety of functions, and so on. Currently, these deviceshave various ports for data transfer. They are used for powering thedevice or backing up data. They are also used for transmitting data ontoand from phones.

Some of these ports support standards which currently have onedifferential pair, D+Diff_pos) and D− (Diff_neg). Upgraded versions ofthese standards may be significantly faster and full duplex. They maysupport a Tx and Rx pair which allows data to be sent without firsthaving to wait for a reply. This enables extremely quick downloads ofdigital video, such as movies and other high-volume data, and makes thedevices even more multimedia-centric. For example, multimedia devicemanufacturers are beginning to incorporate these standards into theirphones, and it is expected that users will want to be able to downloador show pictures, videos, and other content directly to an externaldisplay device from their devices (without use of a computer or othercomponent). Micro versions of these standards are also gaining wideacceptance in the marketplace. It is expected that users will want to beable to download multimedia content directly from mobile devices on toan external display device. Thus, it would be desirable to be able tomap digital multimedia content onto micro versions of these standardsfrom a packet-based digital display interface and supply power from thedisplay device to the mobile device simultaneously.

SUMMARY OF THE INVENTION

In one aspect of the invention, methods of enabling transmission ofmultimedia or other types of data and enabling the supply of powerbetween a data source device and an external display device aredescribed. Main link signals of a packet-based interface are mapped to amicro serial interface ID pin. A hot plug detect (HPD) signal of thepacket-based interface is mapped to the MicroUSB2.0 ID pin. Thesemappings enable transport of the data stream from the data source deviceto the external display device. Power is supplied from the externaldisplay device to the source device using a micro serial interfaceconnection while simultaneously transporting the data stream.

In one embodiment, an auxiliary channel positive signal is mapped to afirst differential I/O signal and an auxiliary channel negative signalis mapped to a second differential I/O signal. In another embodiment,sideband communications are completed before main link transmission ofmultimedia content begins. In another embodiment, power is supplied overa packet-based interface power pin to a Vbus pin. In yet anotherembodiment, an auxiliary/HPD controller is utilized for mapping the HPDsignal and for mapping the auxiliary channel signals.

Another aspect of the present invention is a cable adaptor forconnecting a data source device with a display device. The cable adaptorhas a packet-based interface connector at a first end having a positivemain link pin, a negative main link pin, a positive auxiliary channelpin, and a negative auxiliary channel pin. At the second end, the cableadaptor has a micro serial interface connector, wherein multimediacontent is transmitted over the adaptor and electrical power is suppliedover the adaptor simultaneously. The adaptor also has an auxiliary andHPD controller having a specific number of signals.

In one embodiment, the packet-based interface connector has a pin forHPD signals. The main link positive signal is mapped to a positivedifferential signal. In one embodiment, the auxiliary and HPD controllerhas two differential input/output signals, an ID signal, and an HPDsignal.

In one aspect of the invention, methods of enabling transmission ofmultimedia or other types of data and enabling the supply of powerbetween a data source device and an external display device aredescribed. In particular embodiments suitable for enabling more than onepower level to be transmitted to a source device by a display aredisclosed.

In one embodiment, a multimedia data source device comprises amultimedia data processor suitable for providing multimedia data andoperating using a negotiated power from an external display device. Themultimedia data source device also comprises power level determinationcircuitry for negotiating a power level to be received from the externaldisplay device enabling operating of the multimedia data source device.The multimedia data source device also comprises an interface systemsuitable for coupling with the external display device. The interfaceenabling a main data link, a power connection suitable for receiving thenegotiated power from the external display device, and an auxiliarychannel suitable for transmitting sideband data between the externaldisplay device and the source device.

Another aspect of the present invention is a multimedia data displaydevice with a display media suitable for displaying multimedia contentand power level determination circuitry for negotiating a power level tobe transmitted by the display device to a source device to enableoperation of source. Further comprising an interface system suitable forcoupling the display with the external display device. The interfaceenabling a main data link, a power connection suitable for transmittingthe negotiated power to a source device, and an auxiliary channelsuitable for transmitting sideband data between the display device andthe source device.

In another aspect, the invention describes a method of enabling powertransmission at a negotiated power level from a display device to aconnected source device. The method includes establishing a connectionbetween a multimedia data source device and an external display device,the connection comprising a power connection and an auxiliary dataconnection. Then a power level is negotiated for power transmission fromthe display device to the source device to enable operation of themultimedia data source. Once negotiated, the negotiated power istransmitted from the external display device to the source device.

General aspects of the invention include, but are not limited tomethods, systems, apparatus, and computer-readable media for enablingmessage transmission in multimedia device networks.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and the advantages thereof may best be understood byreference to the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a simplified network diagram showing a multimedia deviceconnected to an external display device via a cable in accordance withone embodiment;

FIG. 2 is a block diagram of a serial interface receiver connectorcomponent of a multimedia device;

FIG. 3A is a pin diagram of a packet-based display interface receiverconnector of an external display in accordance with one embodiment;

FIG. 3B is a block diagram of a serial interface receiving connector ona external display;

FIG. 4 is a pin diagram of a packet-based display interface receiverconnector of an external display in accordance with an alternativeembodiment;

FIG. 5 is a detailed block diagram showing in greater detail thecomponents of FIG. 1 in accordance with one embodiment;

FIG. 6 is a block diagram of a packet-based interface source plugconnector in accordance with an alternative embodiment;

FIG. 7 is a flow diagram of a process of transmitting data and providingpower between an external display device and a multimedia device inaccordance with one embodiment;

FIG. 8 is a flow diagram of a process of supplying power from theexternal display to the multimedia device in accordance with oneembodiment;

FIG. 9 is an overview block diagram showing a connection between amultimedia device and an external display device in accordance with oneembodiment;

FIG. 10 is a block diagram showing in greater detail the componentsshown in FIG. 9 in accordance with one embodiment;

FIG. 11 is a block diagram of a device PCB having a passivebi-directional switch (multiplexer) in accordance with one embodiment;

FIG. 12 is a block diagram of a device PCB where a packet-based ML TXPHY and a USB PHY share the same pads in accordance with an alternativeembodiment;

FIG. 13 is a simplified network diagram showing a multimedia deviceconnected to an external display device via a cable in accordance withone embodiment; and

FIG. 14 is a flow diagram of a process of providing power from anexternal display device to a multimedia device in accordance with oneembodiment.

In the drawings, like reference numerals are sometimes used to designatelike structural elements. It should also be appreciated that thedepictions in the figures are diagrammatic and not to scale.

DETAILED DESCRIPTION OF THE INVENTION

Reference is made to particular embodiments of the invention. Oneexample of which is illustrated in he accompanying drawings. While theinvention will be described in conjunction with the particularembodiment, it will be understood that it is not intended to limit theinvention to the described embodiment. To the contrary, it is intendedto cover alternatives, modifications, and equivalents as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

Aspects of the invention pertain to methods and apparatus for enablingtransmission of data from a source to sink and simultaneously enablingthe supply of power from the sink to the source. The source supports apacket-based interface and an enhanced serial interface. The sinksupports the same packet-based interface and is a serial interface hostand is able to supply power to the source, as described in greaterdetail below. The invention is an apparatus, referred to as a passivecable adaptor that has an enhanced serial interface plug connection atone end that connects to a device, such as a multimedia device, and atthe other end has two connectors: a packet-based interface plugconnection and a serial interface plug connection, both of which connectto the external display device.

In one embodiment, methods for mapping a 1-lane main link packet-baseddisplay signal onto a enhanced serial interface connector for enablingconnectivity from a packet-based source packet-based displayinterface/enhanced serial interface equipped handheld device to anexternal packet-based display interface-enabled and serial interfacedisplay device are described. The methods allow for the simultaneousoperations of a packet-based source interface isochronous transport ofmultimedia audio-visual (AV) streams and serial interface operationwhile the mobile phone is powered by the external display device. The AVstream may have High-bandwidth Digital Content Protection (HDCP) contentprotection.

FIG. 1 is a simplified network diagram showing a multimedia deviceconnected to an external display, such as a TV, via a passive cableadaptor. The various embodiments described herein related to methods andcomponents in the passive cable adaptor. A multimedia device 102 is amultimedia-centric computing device capable of performing numerousfunctions in addition to being a mobile phone. In other embodiments, itmay be an IP-enabled computing device, such as a tablet or mobile gamingdevice. In other embodiments, it may not be IP-enabled and may simply bea multimedia handheld device used primarily for taking pictures andvideo, storing and watching movies and other audio-visual content,storing and reading electronic versions of books and periodicals(e-books), storing and listening to music, and so on. Multimedia device102 is a packet-based interface source (hereafter “packet-based source”)and an enhanced serial interface capable device. Component 110 inmultimedia device 102 is a standard enhanced serial interface receivingconnector, the type of connector many mobile phone and handheld devicemanufactures are or will be providing on their devices due to itssignificant advantage over the previous generation serial interface.This connector or component 110 is commonly referred to as simply aserial interface port. As noted, in one embodiment, multimedia device102 is a source device for multimedia content that transmits data to asink device, where the content is played or displayed.

In one embodiment, the sink device is an external display device 104,such as a TV or a computer monitor. In the described embodiments,external device 104 is a standard serial interface host. It may also bean enhanced serial interface host, which would make it capable of beinga host for 2.0 (since 3.0 is a superset of 2.0). Display device 104 hastwo connectors relevant to various embodiments of the present invention.One is a packet-based display interface source receiver connector 116.The other is a serial interface receiver connector 118. These connectorsare described in greater detail below.

The external display device 104 and multimedia device 102 are connectedby a passive cable adaptor 106. At one end of cable 106 is an enhancedserial interface plug connector 108 which is capable of coupling toreceiver connector 110 of multimedia device 102. At the other end aretwo plugs: a packet-based interface source plug connector 112 and aserial interface plug connector 114. Plug connector 112 is capable ofcoupling with the interface source's receiving connector 116 and plugconnector 114 can couple with serial interface receiver connector 118.Multimedia content is transmitted from multimedia device 102 to displaydevice 104 where it is displayed and, simultaneously, power is providedfrom display device 104, for example a TV, to multimedia device 102. Theamount of power supplied depends on the configuration and use of pins inreceiver connectors 116 and 118 in display device 104 and in connector110 in multimedia device 102. These configurations are described indetail below. Generally, in the described embodiment, the amount ofpower provided may range from 3.3V/500 mA to a total of 8.3V/500 mA.

FIG. 2 is a block diagram showing pin connector designations of enhancedserial interface receiver connector 110 of multimedia device 102.Enhanced serial interface has a serial interface backward compatibleportion. This portion includes the half-duplex, bi-directional pins, D+202 and D− 204. This differential pair is capable of transmitting dataat 480 Mbps. Also part of this backward compatible portion is a Vbus pin206 and a GND (ground) pin 208. The role of these pins is described inthe figure below.

The enhanced serial interface extension portion is composed of theremaining five pins. There is a high-speed TX+ pin 210 (“HSTX”) andhigh-speed TX− pin 212 pair for transmitting data from a host or sourcedevice, such as multimedia device 102 to a sink or hub device, such asmultimedia device 102 to a sink or hub device, such as external monitor104. HSTX+ 210 and HXTX− 212 are AC-coupled and can transmit data at 5Gbps. A high-speed RX+ pin 214 and a high-speed RX− pin 216 (“HSRX”)comprise a pair for receiving data from a hub/sink device (e.g., TV 104)at the host (e.g., multimedia device 102) and is also AC-coupled and cantransmit data at 5 Gbps. This pair (HSRX+ 214 and HSRX− 216) and thepair HSTX+ pin 210 and HSTX− pin 212 comprise a full-duplex,bi-directional coupling between multimedia device 102 and externaldevice 104. That is, data can be transmitted in both directions at thesame time, unlike in the serial interface protocol, providing for aspeed that is faster than the increase in actual transmission speed (458Mbps vs. 5 Gbps). There is also a GND pin 218 that is part of theenhanced serial interface extension portion.

Moving now to packet-based display interface source receiving connector116 of external display 104, there are five pins as shown in FIG. 3A. Amain link lane0+ (ML0+) pin 302 and a main link lane0− (ML0−) pin 304are used for transmitting data from a source to a sink at 5.5, 2.7, or1.62 Gbps and are AC-coupled. ML0+/− pins are specific to a packet-baseddigital interface described below. There is also an auxiliary channelpair which functions as a bi-directional sideband channel in thepacket-based digital interface protocol. An AUX CH+ pin 306 and AUX CH−pin 308 pair enable 1 Mbps transmission and are half-duplex andbi-directional. There is also a pin 310 for hot plug detect (HPD) fromexternal display device 104 (sink) to multimedia device 102 (source). INthis embodiment, there is no connection for DP_PWR (part of thepacket-based display interface). In one embodiment, the power sourcefrom sink to source is 3.3V/500 mA. The interface referred to herein isa packet-based, serial digital display interface that is open andscalable and supports plug and play. Unlike conventional displayinterfaces that transmit a single video raster plus timing signals(e.g., Vsync, Hsync, DE, etc.), the packet-based interface referred toherein provides multi-stream packet transfer capable of transferring oneor more packet streams simultaneously in the form of virtual pipes orlanes established within a physical link or main link. A number of datastreams are received (from a source device) at a transmitter (acomponent of the physical link) that, if necessary, packetizes each intoa corresponding number of data packets. The data packets are then formedinto corresponding data streams, each of which are passed by way of anassociated data lane to a receiver (also a component of the physicallink).

The link rate (i.e., the data packet transfer rate) for each virtuallink or lane can be optimized for the particular data stream resultingin the physical link carrying data streams, each having an associatedlink rate (each of which may be different depending on the particulardata stream). Thus, the link rate is independent of the native streamrates. In this way, the packet-based interface provides a scalablemedium for the transport of video, graphics, audio, and applicationdata. The interface also supports hot-plug detection (HPD) andautomatically sets the physical link (or pipe) to its optimumtransmission rate. The interface provides for low pin count and purelydigital display interconnect for all displays, including HDTV. Thepacket-based nature of the interface provides scalability to supportmultiple, digital data streams such as multiple video/graphics streamsand audio streams for multimedia applications. In addition, a USBtransport for peripheral attachment and display control can be providedwithout the need for additional cabling.

One feature of the packet-based, display interface is that it has anauxiliary channel logical sub layer. The major functions of theauxiliary channel include data encoding and decoding, framing/de-framingof data and two options for auxiliary channel protocol. One is astandalone protocol (limited to link setup/management functions in apoint-to-point topology) which is a lightweight protocol that can bemanaged by the Link Layer state-machine or firmware. The other is anextended protocol that supports other data types such as USB traffic andtopologies such as daisy-chained sink devices. In the describedembodiment, the packet-based interface signal is transmitted over asingle lane on the main link. In other embodiments, two or four lanesmay be used over the main link. In this case, the auxiliary channel canbe disabled and can then be mapped to D+ and D−, which can then providetwo main link lanes. Further details on the packet-based displayinterface are described in patent application Ser. No. 11/742,222,titled “Integrated Packet-Based Video Display Interface and Methods andUse Thereof,” filed on Apr. 30, 2007 (U.S. Published Application No.2007/0200860). Packet-based interface configuration data fields that arerelevant to voltage shifts are shown in Table 1 below.

Returning now to the figures, FIG. 3B shows a serial interface receivingconnector 118 on an external display 104. These pins correspond to theserial interface backward compatible portion of connector 110 in FIG. 2.There is a differential pair composed of a D+ pin 312 and a D− pin 314that enable 480 Mbps transmission and are half-duplex andbi-directional. There is also a Vbus pin 316 for power (5V/500 mA forserial interface) and a GND pin 318.

In another embodiment, connector 116 of external display device 104 mayhave a different configuration when multimedia device 102 gets powerfrom device 104 and when device 104 does not have a downstream USB port(i.e., no serial interface connection from external display device 104to multimedia device 102). In this embodiment, phone 102 receives powerfrom DP_PWR pin as well as from Vbus pin 316.

A configuration connection 116 is shown in FIG. 4. Here the ML0+ pin 402and ML0− pin 404 are the same as in FIG. 3A. The AUX CH+ pin 406 is alsothe same. Pin 409 is used for HPD. Pin 410 is sued solely for DP_PWR andis not shared with HPD. This is also the case with FIG. 3A, describingthe first embodiment, where external display 104 has a USB downstreamport with Vbus power. Recall that in the first embodiment, power isprovided to multimedia device 102 via Vbus pin 316 on serial interface,that is, the backward-compatible connection portion. When externaldisplay device 104 is only a serial interface host (not a enhancedserial interface host), the power is limited to 5V/500 mA. In cableadaptor 106, AUX− (pin 408) and HPD (pin 409) are connected or mutexed,shown in more detail in FIG. 6 below.

FIG. 5 is a detailed block diagram shown in greater detail thecomponents of FIG. 1 in accordance with one embodiment. The three basiccomponents are multimedia device 102 shown as box 502, external displaydevice 104 shown as box 504, and passive adaptor cable 106 shown as area506. Connected to box 504 is enhanced serial interface receiverconnector 110 shown as box 508. Packet-based interface source receiverconnector 116 and serial interface receiver connector 118 are part ofexternal display device 104.

Adaptor cable 106 is the data communication and simultaneouspower-supplying device between multimedia device 102 and display device104. As noted above, it has an enhanced serial interface plug connector108 on one end that connects to receiver connector 110 on multimediadevice 102. On the other end that connects to receiver connector 110 onmultimedia device 102. On the other end are packet-based interfacesource plug connector 112 that plugs into receiver connector 116 andserial interface plug connector 114 that plugs into receiver connector118.

The pins in all the receiver connectors and plug connectors aredescribed in FIGS. 2, 3, and 4 and are shown in more detail in FIG. 5(like number reference numbers are used for ease of explanation). Plugconnector 108 has pins 202 and 218 as described in FIG. 2A. Interfacesource plug connector 112 has pins 302 and 310. Serial interface plugconnector 114 has pins 312 and 318 as shown in FIG. 2B.

Multimedia device 102 has numerous components relevant to embodiments ofthe present invention. Starting with HSTX+ pin 210, a connection or line514 leads to Main Link (ML) TX/enhanced serial interface HSTX component(as described above, ML pertains to the packet-based interface). Pin 210maps to pin 302 to ML0+ having line 518 leading to Main Link RX inexternal display device 104. HSTX− pin 212 has a line 516 leading to theMain Link TX component. Pin 212 maps to pin 304 on display device 104 onthe ML0− line to Main Link RX. HSRX+ pin 212 has a line 516 leading tothe Main Link RX in external display device 104. HSRX+ pin 214 has line522 leading to an AUX CH TRX/enhanced serial interface HSRX component.Pin 214 connects to AUX+ pin 306 having AUX+ line 526 leading to an AUXCH TRX component. There is also a stub on line 526 leading to the AUX CHTRX. The last pin of enhanced serial interface plug connector is GND pin218 having an HPD_IN line 530 leading to an HPD Detector. Off of line530 are two stubs, one labeled HPD_DETECT_CTRL that also leads to theHPD Detector. Pin 218 connects with pin 310 corresponding to an HPD pinhaving line 532 leading to an HPD Driver in display device 104. DP_PWRhas a DP_PWR_OUT line 534 leading to DP_PWR Provider component.

The remaining pins are part of the serial interface backward compatibleportion. D+ pin 202 has a D+ line 536 leading to a serial interfaceDownstream (differential pair D+/D−) component. A corresponding D− pint204 has a line 538 leading to the same downstream component. Pins 202and 204 connect with D+ pin 312 and D− pin 314 on external displaydevice 104. Each has a line 540 and 542, respectively, that lead to aserial interface Upstream D+/D− component. A Vbus pin 206 has a Vbus_inline 544 leading to USB Vbus Consumer component. Pin 206 connects withVbus pin 316 on display device 104 which has line 546 leading to a USBVbus Provider component. Finally, GND pin 208 has a line 548 leading toground as shown and is connected to pin 318 having a line 550 leading toground in display device 104.

FIG. 6 shows a second embodiment of packet-based interface source plugconnector 112. Only the portion of connector 112 that is different fromthe embodiment in FIG. 5 is shown. At the top is shown AUX+ pin 306having line 526 leading to the AUX CH TRX component with a stub forSRC_DETECT leading to a Source Detector. In this embodiment, HPD andAUX− are connected or multiplexed at 602 inside cable adaptor 106,specifically within connector 112. DP_PWR pin 410 does not share its pinwith any other input/output. The other three pins, 402, 404, and 406,are the same as 302, 304, and 306 in FIG. 3A. In this embodiment,multimedia device 102 does not support full enhanced serial interfaceoperation using HSTX/HSRX. This is the case even when phone 102 is notin packet-based interface source mode because there is an HPD signalstub 602 of the HSRX-line from multimedia device 102. Other features ofthis embodiment include multimedia device 102 getting powered fromexternal display device 104 when device 104 does not have a USBdownstream port since it receives power from DP_PWR pin 410 (part ofenhanced serial interface) as well as from Vbus pin 316 (part of serialinterface) as shown in FIGS. 3B and 5. Thus, total power to phone 102 is5V/500 mA (or 900 mA if external display is enhanced serial interface)from Vbus pin 316 in addition to 3.3V/500 mA from DP_PWR pin 410. Thisembodiment also supports simultaneous operations of packet-based displayinterface source isochronous transport of AV streams with High BandwidthDigital Content Protection (HCDP) and serial interface.

FIG. 7 is a flow diagram of a process of mapping signals and providingpower between an external display device and a multimedia device inaccordance with one embodiment. In other embodiments, other types ofhandheld devices having enhanced serial interface or a standard serialinterface and packet-based interface ports may be used. As noted above,the external display device may be a high-definition TV or other displaydevice, such as a computer monitor. A user having a multimedia devicewith content on it, such as digital videos or pictures, wants to displaythe content on a larger display, typically an HDTV. At the same time,the user may want to charge the pone without having to plug the phoneinto an electrical outlet. The user would prefer to use a single cablebetween the phone and the display device to simultaneously display ordownload the content and power the phone. However, the user may not beaware of the specific capabilities of the TV or the phone, such aswhether the phone is enhanced serial interface enabled or whether the TVhas a packet-based digital display interface connector.

At step 702, the multimedia device is powered on and, as part of itsnormal operation, it monitors GND pin 218 voltage and Vbus pin 206voltage. The action taken based on this monitoring is described afterstep 704. The passive cable adaptor of the present invention is used toconnect the multimedia device with the external display. The adaptorcable has one end that is an enhanced serial interface plug connectorwhich is inserted or engaged with an enhanced serial interface receivingconnector on the multimedia device. It will not engage with a serialinterface receiving connector. The other end of the cable connects tothe external display, such as an HDTV. The display may or may not beenhanced serial interface equipped and similarly, it may or may not bepacket-based interface-enabled. Once the multimedia device detects thata connection has been made by monitoring these pins, control goes tostep 704 where the external display supplies power to the phoneimmediately if the external display is already powered on or as soon asthe display is turned on. This power is supplied regardless of any otherdata transmissions that may be occurring between the phone and theexternal display, that is, no data needs to be transmitted between thetwo devices for power to be supplied from the external display.

Each pin (GND and Vbus) can be in one of two states: High or Low. Thus,there are four combinations of states or voltage levels. These are shownin boxes 706 to 712. To be complete, the simplest case (and one that ispresumed to not be true because of actions taken at step 702), no deviceis connected to the multimedia device as shown in box 706. In this casethe multimedia device detects that the GND pin and the Vbus pin are bothlow, thus nothing is connected as indicated in box 714 and the processends. If the GND pin is H (“pulled up”) and the Vbus pin is H, as shownin box 708, it is determined by the multimedia device that the externaldisplay or device connected to via the passive adapter cable has apacket-based digital display interface and is a USB host as indicated bybox 716. The GND pin can only be pulled up if the device has apacket-based digital display interface. If the GND pin is H and the Vbuspin is L, it is determined that the external display only has apacket-based digital display interface and is not a USB host asindicated in box 718. Finally, if the GND pin is L and the Vbus pin is Has shown in box 712, the multimedia device knows that the externaldisplay is a USB host only as indicated in box 720 and the process iscomplete; no mapping takes place.

If the external device has a packet-based digital display interface(boxes 716 and 718), control goes to step 722 where a mapping isperformed between the packet-based interface signal and the enhancedserial interface connector signal. At step 722 the HSTX signals aremapped to ML0+/− signals. As can be derived from the figures above,HSTX+ signals are mapped to ML0+ and HSTX− maps to ML0−. The HSRXsignals are mapped to AUX+/− signals. More specifically, HSRX+ maps toAUX+ and HSRX− maps to AUX−. This is the mapping that takes placebetween the packet-based interface and enhanced serial interface andenables transport of AV streams or other types of digital data (withHDCP) between the phone and TV. These steps are done simultaneously withsupplying power performed at step 704. At this stage the multimediadevice and TV are connected and the TV is displaying data from the phoneeither via the packet-based digital display interface (and HXTX/HSRX) orvia USB, and power is being supplied to the phone, as described ingreater detail in FIG. 8.

FIG. 8 is a flow diagram of a process of supplying power from theexternal display to the multimedia device in accordance with oneembodiment. It shows in greater detail step 704 of FIG. 7. At step 802it is determined whether the external display device ahs serialinterface downstream capability. This can be done using techniques knownin the art. If the display does have downstream serial interfacecapability, then control goes to step 804 where power is supplied viathe Vbus pin on the serial interface backward-compatible connector andthrough the DP_PWR pin, part of the packet-based digital displayinterface receiving connector. In one embodiment, the amount of power is5V/500 mA. If the external display is an enhanced serial interface host,the power may be 5V/900 mA. If the external display does not have serialinterface downstream capability, control goes to step 806 where power issupplied to the multimedia device on through the DP_PWR pin.

In another embodiment, if the multimedia device or other sourcedetermines that the HPD_DETECT_CTRL is low, this is an indication thatthe external display device is not an enhanced serial interface host.This determination can be made by the HPD Detector component 552. IfHPD_DETECT_CTRL is not low, then the multimedia device has determinedthat the external display is an enhanced serial interface host.

Micro-Serial Interface Mapping

In another embodiment, packet-based digital display interface signalsare mapped to signals of a micro version of the serial interfaceconnector (hereafter “micro serial interface”). A micro serial interfaceconnector has a smaller connector and is suitable for mobile andhandheld devices for which a smaller connector would be more suitablethan the standard serial connector. FIG. 9 is an overview block diagramshowing a connection between a multimedia device and an external displaydevice in accordance with one embodiment. A multimedia device 920 isconnected to an external display device 922 via micro serialinterface-to-packet-based interface cable adaptor 924. Multimedia device920 has a micro serial interface receiver port 926. External displaydevice 922 has a mated packet-based digital display interface receiverport 928. Cable 924 has a micro serial interface connector 932 at oneend that couples with receiver port 926 on multimedia device 920 and apacket-based display interface connector 930 (at the other end) thatcouples with receiver port 928 on external display 922. As with theembodiments described above, multimedia device 920 acts as apacket-based interface source device (i.e., it provides the multimediaor AV data stream, video, audio, graphics, etc.). It may also act as aserial interface device. External display device 922, such as an HDTVmay act as a packet-based digital interface sink device (i.e., itreceives the multimedia/AV stream and displays it) and as a serialinterface host device.

As described above, the packet-based digital interface protocol allowssideband communications that occur over auxiliary channels (AUX CH) tobe completed before beginning main link transmission of the multimediaor other type of data. This allows the main link and the auxiliarychannels to share the same differential pair (D+ and D−). As describedabove in FIG. 3B, a standard (i.e., not micro) serial interfaceconnector has four pins: D+, D− (480 Mbps, half-duplex bi-directional),Vbus (power, 5V), and GND. Micro serial interface connector 932 has fivepins. This type of connector is becoming increasingly common on handhelddevices, such as multimedia devices, video cameras, gaming devices, andother portable devices. Four of the pins in connector 932 are the sameas those in the standard serial interface and have the samecharacteristics, but with the addition of one pin that may be referredto as an “ID” pin for serial interface mobile support.

This ID pin is used for supporting serial interface mobile support onserial interface devices that can function either as a standard serialinterface device or as a limited serial interface device. In oneembodiment of the micro serial interface mapping technique describedherein, this ID pin is used for mapping hot plug detect (HPD). That is,HPD (part of the packet-based digital display interface) is mapped tothe ID pin of micro serial interface connector 932. The differentialpair, D+ and D−, of micro serial interface, is mapped to the main link(ML) of the packet-based display interface communication 930. Theauxiliary channel, AUX+ and AUX−, is mapped to the ID pin of microserial interface connector 932. The Vbus pin of micro serial interfaceis mapped to DP_PWR pin of the packet-based display interface. Mappingto the ID pin of micro serial interface involves use of an AUX_HPDcontroller described below.

In one embodiment, a micro serial interface cable adaptor, as shown inFIG. 10, having HPD detection logic, path selection logic, and adifferential switch, is used to connect a micro serial interfaceconnector on the multimedia device to a packet-based display interfaceconnector of an external display device, such as a TV. In thisembodiment, the multimedia device has packet-based display interfaceoutput capability and the external display device is also packet-baseddisplay interface enabled (i.e., it can receive this kind of input). Thecable adaptor having a micro serial interface plug connector at one end,has the ID pin of the micro serial interface connector tied to eitherVbus voltage of the packet-based display interface or leaves the IP pinfloating.

FIG. 10 is a block diagram showing in greater detail the componentsshown in FIG. 9 in accordance with one embodiment. On the left ismultimedia device (packet-based display interface source device) 920having connector 926, a standard micro serial interface connector havingfive pins, as described above. Connector 926 and components inmultimedia device 920 are described first. Vbus pin 934 has a line 936leading to a power circuit component (power consumer) in phone 920. GNDpin 938 leads to ground as shown in phone 920. A D+ pin 940 and D− pin942, comprising a differential pair, have lines 944 and 946,respectively, leading to a packet-based display interface main link (ML)TX lane 0/USB PHY component 948. ID pin 950 has a line 952 leading to acomponent 954 for AUX TX/RX and HPD detection and for serial interfacemobile ID detection.

Now, display device 922, on the right side of FIG. 10 is described. Itis, as noted, a packet-based display interface sink device. It has apacket-based interface connector 928 with various pins: HPD 954, AUX−956, AUX+ 958, ML0− 960, ML0+ 962, GND 964, and DP_PWR (packet-baseddisplay power) 966. These pins have lines which lead to components inexternal display device (sink device) 922 as shown in FIG. 10.

Cable adaptor 924 in the middle of FIG. 10 is now described. It is amicro serial interface to packet-based interface mapping cablecontaining various components. Connector 932 at one end of cable 924connects to the micro serial interface connector 926 of multimediadevice 920. Connector 932 has five pins that couple to the pins inconnector 926, namely, Vbus 934, GND 938, D+ 940, D− 942, and ID 950.The GND pins map to one other (pin 964 to pin 938). The DP_PWR pin 966from external display 922 maps to Vbus pin 934 via a DP_PWR to Vbusregulator component 968. The main link (ML) pins ML0+ 962 and ML0− 960of external display 922 connect to the differential pair, D+ 940 and D−942, on the multimedia device 920. More specifically, ML0+ maps to D+and ML0− maps to D−, via lines 970 and 972, respectively.

In one embodiment, the MicroUSB to packet-based display interfaceadaptor cable 924 has an AUX_HPD Controller 974 which has four signals.An AUX+ pin 958 and AUX− pin 956 (corresponding to the packet-basedinterface connector 930) are each differential IO, as shown incontroller 974. The HPD pin 954 leads to a single-ended input incontroller 974. On the micro serial interface connector 932 end, the IDpin 950 also leads to a single-ended IO in controller 974 which is alsotri-stateable.

Controller 974 performs various functions. In one embodiment it performsconversion between single-ended AUX CH signal (on the multimedia deviceside) and the differential AUX CH signal (on the external display deviceside). Controller 974 also forwards the HPD signal from display device922 to multimedia device 920. More specifically, when external display922 generates an HPD pulse while an auxiliary channel (AUX CH)transaction is in progress in one embodiment, AUX_HPD Controller 974forwards the HPD pulse as soon as the AUX reply transaction is completed(or if there is no reply, an AUX reply time-out occurs). In oneembodiment, Controller 974 leaves the output portion of ID pin 950tri-stated by default. With a resistor (e.g. 200 kΩ) as shown in FIG.10.

In one embodiment, multimedia device 920, or any device with a microserial interface connector and packet-based interface source capability,upon detecting Logic High level on ID pin 950 (a feature of the microserial interface standard), may discover the presence of packet-basedinterface-to-micro serial interface cable adaptor 924 by variousfeatures. One is by weakly pulling down the ID signal via a 200 kΩresistor and verifying that the ID signal remains at the Logic Highlevel. In this manner, multimedia device 920 can verify that the IDsignal is not floating, which indicates that adaptor cable 924 isconnected. In another embodiment, the ID signal may be pulled down via a20 kΩ resistor, followed by a verification that the ID signal is pulleddown to Logic Low level, thereby indicating that the ID signal is nottied to Vbus 934. This also indicates that cable adaptor 924 isconnected to multimedia device 920.

Multimedia device 920, having packet-based display interface-over-microserial interface capability, interoperates with regular packet-baseddisplay interface external displays. As with other packet-basedinterface source devices, multimedia device 920 can support EDID read,audio/video stream transport, and HDCP content protection of premium A/Vstream content. At 5.4 Gbps per lane (at High Bit Rate 2), packet-basedinterface-over-micro serial interface cable adaptor 924 is capable oftransporting FHD60 Hz of uncompressed video stream.

In one embodiment, cable adaptor 924 is capable of performing an AUX CHhandshake for discovering whether a high-voltage external display deviceis present. This can be enabled as described below. A packet-basedinterface downstream device (such as display device 922), acting as aDP_PWR (power) producer, generates 3.3V by defaults on DP_PWR pin 966via connectors 928/930 (mated packet-based interface connector),according to the packet-based interface standard described above. Adownstream device that is capable of generating a higher voltage, suchas 12V+/− 10% on DP_PWR pin 966, indicates that is has this capabilityby setting a 12V_DP_PWR CAP bit (Bit 0) of a DP_PWR VOLTAGE_CAP field to1 (DP_PWR_ VOLTAGE_CAP field corresponds to packet-based interfaceconfiguration data address 00010h). The upstream device, multimediadevice 920, may enable the 12V_DP_PWR of the downstream device bysetting the 12V_DP_PWR_REQUEST bit (Bit 0) of aDP_PWR_VOLTAGE_SHIFT_REQUEST field to 1 (packet-based configuration dataaddress 00119h). Clearing the bit to 0 sets the DP_PWR voltage back to +3.3V+/− 10%. The downstream display device that is capable of generating12V on DP_PWR pin 966 must be able to transition between 3.3V and 12Vwithout causing a voltage spike on the DP_PWR power rail. In oneembodiment, multimedia device 920 (upstream device) that requests aDP_PWR voltage shift avoids power-on reset and retains its states duringthe DP_PWR voltage shift.

Table 1 shows the packet-based interface configuration data fields thatare relevant to DP_PWR voltage shifts in accordance with one embodiment.Although the DP_PWR (power) voltage shift of external display device 922(downstream device) is of primary relevance to the packet-basedinterface signal mapping over micro serial interface cable adaptor 924,for completeness, Table 1 shows the fields for the power voltage shiftof multimedia device 920 as well.

TABLE 1 ADDRESS MAPPING FOR PACKET-BASED INTERFACE CONFIG DATA (CD) CDRead/Write over Address Definition AUX CH 00010h DP_PWR_VOLTAGE_CAP Readonly Bit 0 - 12V_DP_PWR_CAP 1 - Downstream device capable of producing12 V +/− 10% on the DP_PWR pin of its packet-based interface connector.0 - Downstream device not capable of producing 12 V +/− 10%; 3.3 V +/−10% only. Bits 7:1 = RESERVED 00119hDN_DEVICE_DP_PWR_VOLTAGE_SHIFT_REQUEST Write/Read Bit 0 =DN_DEVICE_12V_DP_PWR_REQUEST 1 - Requests for 12 V output on the DP_PWRpin of the packet- based interface connector of the downstream device.Don't care when DP_PWR_VOLTAGE_CAP field 12_DP_PWR_CAP bit is 0. 0 -Does not request for 12 V output on the DP_PWR pin of the DP connectorof the downstream device. DP_PWR is 3.3 V +/− 10%. Bit 7:1 - RESERVED011Ah UP_DEVICE_DP_PWR_VOLTAGE_CAP_INDICATION Write/Read Bit 0 -UP_DEVICE_12V_DP_PWR_CAP 1 - Indicates to the downstream device thatthis upstream device is capable of producing 12 V +/− 10% on the DP_PWRpin of its packet-based interface connector. 0 - Indicates to thedownstream device that this upstream device is not capable of producing12 V +/− 10% on the DP_PWR pin of its packet-based interface connector;3.3 V +/− 10% only. Bits 7:1 = RESERVED 02004hDEVICE_SERVICE_IRQ_VECTOR_ESI1 Bit 0 = Bit 0 =RX_GTC_MSTR_REQ_STATUS_CHANGE Clearable Read The status ofRX_GTX_MSTR_REQ has changed. The Only. RX_GTC_MSTR_REQ is readable at CDAddress 00058h bit 0 (B is cleared Bit 1 = UN_DEVICE_12V_DP_PWR_REQUESTwhen ‘1’ is Bits 7:2 - RESERVED. Read all 0 s written via an AUX CHwrite Transaction.) Bit 1 = Read Only

Addresses 00010h and 00119h are relevant to the DP_PWR voltage shift ofthe (downstream) external display device while 0011Ah and 02004h arerelevant to the upstream device.

As noted above, the same differential pair (D=/−) signal traces 944 and946 in multimedia device 920 may be shared between the packet-baseddisplay interface main link (ML) 0+/− and serial interface D+/D−. In oneembodiment, this may be done by placing a passive bi-directional switch(multiplexer) on the PCB of multimedia device 920. This is shown in FIG.11. In this embodiment, it is important to ensure that placing theswitch in the multimedia device 920 will not cause significant signalquality degradation.

Referring to FIG. 11, micro serial interface connector pins 940 and 942,shown initially in FIG. 10, have differential pair lines, DIFF_POS 1102and DIFF_NEG 1104, (in the cable adaptor, they are D+ 940 and D− 942)leading from the pins to a bi-directional f1315 1106. Switch 1106 has a“1” portion and a “0” portion. DIFF_POS line 1102 leads to the 1 portionand DIFF_NEG line 1104 leads to the 0 portion. Two lines from switch1106, an ML0+ line 1108 and an ML0− line 1110 connect switch 1106 topacket-based interface main link (ML) TXLane0+/− component 1112. Alsoshown are two 50Ω resistors and a Vtx_ML bias which is adjusteddepending on whether packet-based digital display interface cableadaptor 924 is detected or not. A cable adaptor detect signal 1114 istransmitted to switch 1106. A cable adaptor can be detected as connectedto multimedia device 920 using the techniques described above.

A USB D+ line 1116 and a USB D− line 1118 connect switch 1106 with aserial interface D=/− component 1120. This component and component 1112are represented collectively as packet-based interface ML TXLane0/serial interface PHY component 948 in FIG. 10. Also shown in FIG.11 is an optional differential re-driver 1123 in cable adaptor 924.Cable adaptor 924 may also have AC-coupling caps 1124 and 1126. Thesemay also be placed in multimedia device 920.

In another embodiment, the packet-based ML TX PHY and the USB PHY sharethe same pads as shown in FIG. 12. Micro serial interface connector pins940 and 942 have a DIFF_POS line 1122 and DIFF_NEG line 1124 leading toa packet-based ML/USB Dual-Mode PHY component 1126. As in the firstembodiment, cable adaptor 924 may have a differential re-driver 1123. AVtx_ML bias adjusts depending on whether cable adaptor 924 is detected.

In one embodiment, the standard serial interface may be implementedusing USB2.0 and the enhanced serial interface may be implemented usingUSB 3.0. High speed transmission (HSTX) may be implemented by SuperSpeed transmission signals in the USB3.0 standard. Similarly, high speedtransmission (HSRX) may be implemented by SuperSpeed receiver signals inUSB3.0. Micro serial interface may be implemented by the MicroUSB2.0standard for mobile and handheld devices. The mobile support of theserial interface of the described embodiment may be implemented by theOn-The-Go (OTG) pin in the MicroUSB2.0 standard. Of course, otherstandards having a serial interface may also be used to implement thedescribed embodiments.

In another approach, modes of transmitting power, to a source device, atvarious levels is described. For example, as illustrated in FIG. 13, asource multimedia device 1301 is connected with a multimedia displaydevice 1302 using a connector 1303 of a type described herein. Such aconnector 1303 supports the transmission of multimedia data through amain data link (such as the data pair described above), the transmissionof sideband signals through an auxiliary channel, as well as powerconnection such as described above. Numerous ancillary connections suchas those previously described can also form part to the connector 1303.The devices and connections shown here can be of the same type describedin FIG. 1.

In one particular useful implementation, the source multimedia devices1301 can be mobile telephones, gaming devices, handheld devices, as wellas the devices described above.

In one embodiment, the source device includes a data processor 1315suitable for generating or otherwise supplying multimedia content to thedisplay device 1302. This processor is capable of transmittingmultimedia data content to the display through a connector interfacesystem coupled with the connector 1303 enabling the multimedia contentto be transmitted to the display. Also, the source is configured toreceive power from the display device through the connector 1303. Also,the source can include power level determination circuitry 1316 which isconfigured to enable the desired power to be transmitted to the sourcefrom the display. It is pointed out that in some embodiments, the powerlevel determination circuitry 1316 can instead form part of the displaydevice 1302.

In many common implementations such handheld devices 1301 operated using3.3 V power using current on the order of about 500 mA at about 1.5 W.However, for certain devices, greater current levels are required. It isto be noted that the power connections described herein use powerconnections of a finite diameter and thus can impose a limit on thecurrent transmitted by such connectors. This problem becomes worse aslonger connectors 1303 are used. Moreover, for some devices, greatercurrent levels are required.

The present invention can take advantage of particular types of displaydevices configured to address this problem. Display devices can beconfigured to transmit power at a number of different power levelsdepending on the device configuration. Thus, display device embodimentscan be configured to transmit power at several different voltage levels.This can be matched up with voltage levels that a source device canoperate in consonance with.

In one example implementation, a display 1302 is configured to supportpower transmission at a multiplicity of different levels. For example,as shown here the display 1302 includes a power configuration field 1320that describes the power transmission capabilities of the displaydevice. For example, the field can include an array of memory registers1321 that are used to store the various power capabilities supported bythe display. In one example, the power configuration field can comprisea set of read/write registers. As shown here, the display can supportpower transmission at 3.3V, 5V, 12V, 18V, and has some number ofreserved address spaces suitable for other power levels.

In complementary example, a source device 1301 is configured to supportoperating power at a multiplicity of different levels. For example, asshown here the source 1301 includes a power capacity field 1310 thatdescribes the operating power capability of the source. For example, thefield can include an array of memory registers 1311 that are used tostore the various operating power levels supported by the display. Inone example, the power capacity field 1310 can comprise a set of readonly registers. As shown here, the source can support operating powertransmission levels of 3.3V, 5V, 12V, 18V, and has some number ofreserved address spaces suitable for other power levels.

Thus, a supported power transmission capability of the display device1302 can be synchronized with a supported operating power level of thesource device 1301. In embodiments of the invention, a priority systemcan be used to identify preferred voltage levels for a source devicethereby enabling a preferred power level to be supplied in preference toa less preferred power level.

FIG. 14 is a flow diagram that describes one possible implementationmethodology suitable for use in accordance with the principles of thepresent invention.

In use, a source multimedia device 1301 is coupled with a display device1302 using an appropriately configured connector. A connection isthereby established between a multimedia source 1301 and a displaydevice 1302 (Step 1401). For example, a hot plug detect (HPD) messagecan identify that the connection between source 1301 and display 1302 ismade. A handshaking protocol (Step 1403) can be performed to identifyconnections, capabilities, and modes of communication between the source1301 and display 1302. For example, a hot plug detect (HPD) message canidentify that the connection between source 1301 and display 1302 ismade and the handshake can be used to establish discover thecharacteristic of the devices 1301, 1302 as well as specify operatingparameters and characteristics. Typically, the handshake will beimplemented as a set of messages and acknowledgements sent via theauxiliary channel.

Importantly, a power level is negotiated between the source and display(Step 1405). This is the power level in which power will be communicatedfrom display to the source device. Typically, this is accomplishedduring a handshaking protocol but need not be so.

In one example process such negotiation can be accomplished as follows.A starting default power level is used at the beginning of thenegotiation. For example, 3.3V can operate as the starting power level.The source device will access the display power capability. For example,the source device 1301 can read the registers of the display powerconfiguration field 1320. If the 3.3V power level is not compatible withboth source and display another further negotiation occurs until acompatible power level is determined. For example, where both the source1301 and the display 1302 are operable at a voltage level of 12V, thatlevel can be used. In addition, where a priority is specified by thesource device, and several power levels satisfy the display and sourcecapabilities, a preferred power level can be provided by the display.

If no compatible power level can be determined the source device willuse its local power source (i.e., typically a battery) to power thesource device 1301.

Once a negotiated power is determined, the display 1302 transmits powerto the source device 1301 via the power lines of the connector 1303(Step 1407). For example, once a power level is negotiated, the sourcecan send a message via the auxiliary channel indicating that the sourceis to send power at the negotiated level.

The display 1202 will send an ACK message via the auxiliary channel. Thedisplay will switch to or otherwise implement the negotiated power(e.g., 12V). The negotiated power will be sent from display 1202 to thesource device 1201 which receives the power and can use this power tooperate the source systems. As can be expected the power is supplied atthe same time as multimedia data is transmitted from source to display.

In another implementation, the power level determining circuitry 1316 ofthe source device 1201 can be configured with some added capacityenabling the following method embodiment. The power level determiningcircuitry 1316 of the source device 1201 can include a current leveldetector. In one such embodiment, during a handshaking protocol thepower level can also be negotiated between the source and display.

In one example process such negotiation can be accomplished as follows.A starting default power level is used at the beginning of thenegotiation. For example, 3.3V can operate as the starting power level.The display will provide the power at 3.3V (or at some other supportedpower level) and the source device will determine an associated currentlevel as supplied through the power line of the connector. In oneimplementation, the source can examine each power level supported by thedisplay device. In other words each supported power level is supplied tothe source and a current level is determined for each power level. Whena desired or preferred current level is achieved, a negotiated powerlevel is thereby determined and supplied to the source device.

In another implementation, the source can calculate the relationship ofthe supplied voltage to the actual current received at the source. Thisrelationship can be used to calculate anticipated current based on thevoltage supplied by the display device. In such a case, the source 1301can again access the display power configuration field 1320 and use asimilar calculation to approximate the current level produced at eachvoltage level supported by the display device 1302. For example, if a3.3V power level produces only about 140 mA of current by the sourcerequires a current of about 500 mA, greater voltage will be required.Further negotiation occurs until a compatible power level is determined.For example, where both the source 1301 and the display 1302 areoperable at a voltage level of 12V, that level can be used to generatethe desired 500 mA. Also, as before if no compatible power level can bedetermined, the source device 1301 will use its local power source(i.e., typically a battery) to power the source device.

In addition, embodiments of the present invention further relate tointegrated circuits and chips (including system on a chip (SOC)) and/orchip sets or packages. By way of example, each of the devices describedherein may include an integrated circuit chip or SOC for use inimplementing the described embodiments and similar embodiments.Embodiments may also relate to computer storage products with acomputer-readable medium that has computer code thereon for performingvarious computer-implemented operations. The media and computer code maybe those specially designed and constructed for the purposes of thepresent invention, or they may be of the kind well known and availableto those having skill in the computer software arts. Examples oftangible computer-readable media include, but are not limited to:magnetic media such as hard disks, floppy disks, and magnetic tape;optical media such as CD-ROMs and holographic devices; magneto-opticalmedia such as floptical disks; and hardware devices that are speciallyconfigured to store and execute program code, such asapplication-specific integrated circuits (ASICs), programmable logicdevices (PLDs) and ROM and RAM devices. Examples of computer codeinclude machine code, such as produced by a compiler, and filescontaining higher level code that are executed by a computer using aninterpreter. Computer readable media may also be computer codetransmitted by a computer data signal embodied in a carrier wave andrepresenting a sequence of instructions that are executable by aprocessor. In addition to chips, chip systems, and chip sets, theinvention can be embodied as firmware written to said chips and suitablefor performing the processes just described.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the invention.However, it will be apparent to one skilled in the art that the specificdetails are not required in order to practice the invention. Thus, theforegoing descriptions of specific embodiments of the present inventionare presented for purposes of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formsdisclosed. It will be apparent to one of ordinary skill in the art thatmany modifications and variations are possible in view of the aboveteachings.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with various modification as are suited to theparticular use contemplated. It is intended that the scope of theinvention by defined by the following claims and their equivalents.

What is claimed is:
 1. A multimedia data source device, comprising: amemory to store power level information describing operating powerlevels supported by the multimedia data source device; power leveldetermination circuitry to negotiate a power level to be received froman external display device into the multimedia data source device toenable operation of the multimedia data source device at a negotiatedpower level, the power level negotiated based on the stored information;a multimedia data processor to provide multimedia data and to operateusing power at the negotiated power level from the external displaydevice; and an interface system to couple with the external displaydevice, the interface system including: a main data link to transmit themultimedia data between the multimedia data source device and theexternal display device; a power connector to receive the power at thenegotiated power level from the external display device when saidexternal display device is connected with the multimedia data sourcedevice; and an auxiliary channel to transmit sideband data between theexternal display device and the multimedia data source device, saidsideband data including power negotiation messages, wherein the powerlevel determination circuitry enables the multimedia data source deviceto: obtain from the external display device power level informationconcerning power levels supported by the external display device;compare the power level information obtained from the external displaydevice with the power level information stored in the memory of themultimedia data source device; and negotiate, based on the comparedpower level information, a power level for use that is a power levelsupported by both the external display device and by the multimedia datasource device.
 2. The multimedia data source device of claim 1, whereinthe power level determination circuitry enables the multimedia datasource device to: receive from the display device ranking informationthat ranks the power levels supported by the external display deviceaccording to a priority schemein which a first power level of the powerlevels supported by the external display device has a higher prioritythan one or more second power levels of the power levels supported bythe external display device, and select the first power level as theselected power level in response to recognizing that the first powerlevel has a higher priority than the one or more second power levels. 3.The multimedia data source device of claim 1, wherein the interfacesystem includes circuitry to direct performance of an auxiliary channelhandshake operation, the auxiliary channel handshake operation todiscover whether the external display device is capable of providingvarying levels of power.
 4. The multimedia data source device of claim1, wherein the power level determination circuitry is arranged to:determine current levels supplied by various voltage levels supported bythe external display device; and negotiate a current level to bereceived by the multimedia data source device such that the negotiatedcurrent level is one of: a current level supported by both the externaldisplay device and by the multimedia data source device, and a currentlevel supplied by a local battery of the multimedia data source device.5. A method to enable transmission of negotiated power to a multimediadata source device from an external display device connected to themultimedia data source device, the method comprising: storing, on themultimedia data source device, power level information describingoperating power levels supported by the multimedia data source device;establishing a connection between the multimedia data source device andthe external display device, the established connection including apower connection and an auxiliary data connection; negotiating a powerlevel for power transmission from the external display device to themultimedia data source device to enable operation of the multimedia datasource, wherein the negotiating includes: obtaining from the externaldisplay device power level information describing power levels supportedby the external display device; comparing the power level informationobtained from the external display device with the power levelinformation stored on the multimedia data source device; and selecting,based on the compared power level information, a power level for usethat is a power level supported by both the external display device andby the multimedia data source device; and supplying power at theselected power level from the external display device to the sourcedevice.
 6. The method of claim 5, wherein the established connectionfurther includes a main link data connection to transport a multimediadata stream, and supplying power at the negotiated power level includessupplying the power through a power connector of a micro serialinterface connection while transporting the multimedia data streamthrough the main link data connection.
 7. The method of claim 5, whereinthe established connection further includes a micro serial interfaceconnection to transport packetized multimedia data, and supplying powerat the negotiated power level includes supplying the power through apower connector of a micro serial interface connection whiletransporting the packetized multimedia data through the main link dataconnection.
 8. The method of claim 5, wherein: the negotiating includesreceiving from the display device ranking information that ranks thepower levels supported by the external display device according to apriority in which a first power level of the power levels supported bythe external display device has a higher priority than one or moresecond power levels of the power levels supported by the externaldisplay device, and selecting the selected power level includesselecting the first power level in response to recognizing that thefirst power level has a higher priority than the one or more secondpower levels.
 9. The method of claim 5, wherein the power levelinformation concerning power levels supported by the external displaydevice is stored in at least one memory register of the external displaydevice, and wherein the power level information concerning the powerlevels supported by the multimedia data source device is stored in atleast one memory register of the multimedia data source device.
 10. Themethod of claim 5, further comprising: performing an auxiliary channelhandshake to discover whether the external display device capable ofproviding varying levels of power is present.
 11. The method of claim 5,wherein the multimedia data source device is a smartphone having a microserial interface connector and the external display device is atelevision having a packet-based digital display interface connector.12. A non-transitory computer-readable storage medium whose storedcontents configure a multimedia data source device that is connected toan external display device to perform a method, the method comprising:negotiating a level of power that the external display device willsupply to the multimedia data source device to enable operation of themultimedia data source, the negotiating including: obtaining from theexternal display device power level information describing power levelssupported by the external display device; retrieving stored power levelinformation describing operating power levels supported by themultimedia data source device; comparing the power level informationobtained from the external display device with the power levelinformation stored on the multimedia data source device; and selecting,based on the compared power level information, a power level for usethat is a power level supported by both the external display device andby the multimedia data source device; and receiving power at theselected level of power from the external display device.
 13. Thenon-transitory computer-readable storage medium of claim 12, wherein thepower level support information stored on the multimedia data sourcedevice is stored in at least one memory register of the multimedia datasource device and the power level information concerning power levelssupported by the external display device is stored in at least onememory register of the external display device.
 14. The non-transitorycomputer-readable storage medium of claim 12, wherein the multimediadata source device is a smartphone having a micro serial interfaceconnector and the external display device is a television having apacket-based digital display interface connector.
 15. The non-transitorycomputer-readable storage medium of claim 12, wherein the comparing ofvarious ones of the one or more of power levels is performed in aprioritized order starting with a default power level.
 16. Thenon-transitory computer-readable storage medium of claim 12, wherein:the negotiating includes receiving from the display device rankinginformation that ranks the power selecting the selected power levelincludes selecting the first power level in response to recognizing thatthe first power level has a higher priority than the one or more secondpower levels.